The Organic Light Emitting Display (OLED) possesses many outstanding properties of self-illumination, low driving voltage, high luminescence efficiency, short response time, high clarity and contrast, near 180° view angle, wide range of working temperature, applicability of flexible display and large scale full color display. The OLED is considered as the most potential display device.
The OLED can be categorized into two major types according to the driving ways, which are the Passive Matrix OLED (PMOLED) and the Active Matrix OLED (AMOLED), i.e. two types of the direct addressing and the Thin Film Transistor (TFT) matrix addressing. The AMOLED comprises pixels arranged in array and belongs to active display type, which has high lighting efficiency and is generally utilized for the large scale display devices of high resolution.
A OLED display element usually comprises: a substrate, an anode formed on the substrate, a hole injection layer formed on the anode, a hole transport layer formed on the hole injection layer, an emissive layer formed on the hole transport layer, an electron injection layer formed on the emitting layer, an electron transport layer formed on the electron injection layer, a cathode formed on the electron injection layer. The illuminating principle of OLED is the phenomenon that is the illumination due to the carrier injection and recombination under the electric field driving of organic semiconductor illuminating material and illuminating material. Specifically, the OLED display element generally utilizes the ITO transparent electrode and the metal electrode respectively as the anode and the cathode of the display. Under certain voltage driving, the electron and the hole are respectively injected into the electron and hole injection layers from the cathode and the anode. The electron and the hole respectively migrate from the electron and hole transport layers to the emissive layer and bump into each other in the emissive layer to form an exciton to excite the emitting molecule. The latter can illuminate after the radiative relaxation.
Reference is made to FIG. 1, which is a structural schematic view of a conventional top-emitting-light display. The OLED display includes a TFT substrate 100′, the TFT substrate 100′ having a plurality of pixel isolation layers 200′ on a surface thereof, the TFT substrate 100′ having a plurality of OLED emissive layers 300′ on the surface thereof, each OLED emissive layer 300′ having a cathode 400′ on a surface thereof, a cover plate 500′ covered on the pixel isolation layer 200′ and the cathodes 400′, and a sealant 600′ bonding the cover plate 500′ and the TFT substrate 100′. The TFT substrate 100′ includes: a base substrate 110′, the base substrate 110′ having a TFT array layer 120′ on a surface thereof, the TFT array layer 120′ having a planarization layer 130′ cover a surface thereof, and the planarization layer 130′ having a plurality of anodes 140′. The TFT substrate 100′ has a plurality of pixel regions 101′ surrounded by the pixel isolation layers 200′ on the surface thereof. Each pixel region 101′ respectively has the OLED emissive layer 300′ therein. The cover plate 500′ has a light-filter layer 510′. The OLED emissive layers 300′ are generated by printing or evaporating the OLED illuminating material within the pixel regions 101′. Whether it is the manner of printing or evaporating, the oblique light of each pixel region emitted into adjacent pixel regions occurs the light leakage while the OLED emissive layer 300′ lighting, so as to decrease the quality of display.